JPH09199036A - Method and device for adjusting display position of picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a burden for an inspection worker by automatically adjusting a display position by using the same inspection pattern as that of picture (distortion) inspection thereafter. SOLUTION: The center part of a faceplate 2 of a picture tube 1, displaying an inspection pattern having the brightness gravity center in a pattern center, is picked up by a TV camera 3. Based on the obtained picture information, in the case of adjusting a display position of the picture tube 1, an image is picked up so as to place only the one brightness gravity center of the inspection pattern in a visual field of the TV camera 3. Based on the obtained brightness gravity center of the image, a center position of the inspection pattern is obtained, a deviation between the obtained inspection pattern center position and a faceplate center position prestored in a memory is calculated. Based on this deviation amount, a pattern display position adjusting DC level is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the image display position of a picture tube (cathode ray tube), and more specifically to an automatic adjustment method using a TV camera or the like.

[0002]

2. Description of the Related Art In a color picture tube, an electron beam is deflected vertically and horizontally by a deflection yoke to draw an image on a screen surface. At this time, variations in the display position of the image may occur due to variations in the assembling accuracy and the positional accuracy of the components forming the color picture tube. The factors are the assembly accuracy of the electron gun, the fixed position of the electron gun in the color picture tube, the assembly accuracy of the horizontal deflection coil and the vertical deflection coil of the deflection yoke,
The mounting accuracy of the deflection yoke and the color picture tube may be mentioned. Due to these factors, the deflection amount or deflection center of the electron beam on the screen surface varies, and as a result, the display position of the image varies.

On the other hand, in the inspection process in the manufacture of a color picture tube, a predetermined inspection pattern is usually actually projected on the screen surface to inspect and adjust image distortion such as pincushion distortion. Before the image inspection,
It is necessary to make an adjustment to correct the variation in the display position of the image as described above. In other words, by manually adjusting the inspection pattern display position adjustment DC level of the deflection power supply,
It is necessary to accurately display the inspection pattern in the center of the screen.

As a conventional example of such a method for adjusting the display position of an image, there is a method described in Japanese Patent Laid-Open No. 6-168665. In this adjustment method, a horizontal or vertical bright line equal to the horizontal or vertical length of the effective screen is displayed on the screen, and the deflection is performed so that both ends of the bright line coincide with both ends of the effective screen. The DC level of the deflection signal given to the means is adjusted.

[0005]

However, in the above-described conventional technique, the horizontal or vertical bright line is projected by stopping the vertical or horizontal deflection power source.
If the test current (anode current) is the normal raster display current, a large amount of electron beam current concentrates on a narrow bright line, resulting in an overload condition, which may result in phosphor burn-in. Therefore, each time the deflection center is adjusted, it is necessary to reduce the test current below the normal raster display current.

Further, in the horizontal direction and the vertical direction, it is necessary to perform position adjustment by visually observing both ends of each bright line, which makes the work complicated. After the position adjustment is completed, it is necessary to change from the bright line pattern in the horizontal or vertical direction to the normal inspection pattern and to return the test current to the normal raster display current when moving to the image inspection.

Further, in the conventional method in which the operator adjusts the DC level for controlling the center position of the deflection power source while visually measuring the positional deviation of the beam spot, considerable skill is required of the operator. It On the other hand, it is difficult to stably perform highly accurate position adjustment, and there is a problem that it is not suitable for mass production.

The present invention has been made in view of the above situation, and an object thereof is to automatically adjust the display position by using the same inspection pattern as the subsequent image inspection. It is to reduce the burden on inspection workers.

[0009]

According to a display position adjusting method of a picture tube according to the present invention, a central portion of a screen of a picture tube on which an inspection pattern having a luminance center of gravity in the center of the pattern is projected by a TV camera is obtained. When adjusting the display position of the picture tube based on the obtained image information, the image is captured so that only one luminance centroid of the inspection pattern is included in the visual field of the TV camera, and the luminance centroid of the obtained image is obtained. The center position of the inspection pattern is obtained based on the calculated position, the deviation between the obtained center position of the inspection pattern and the screen center position stored in the memory in advance is calculated, and the pattern display position adjustment DC level is adjusted based on this deviation amount. It is characterized by doing.

According to such a display position adjusting method, it is easy to use an inspection pattern that has a plurality of luminance centroids arranged in a matrix including the pattern center and is used for inspecting and adjusting image distortion such as pincushion distortion. The pattern display position can be adjusted. That is, after adjusting the display position, it is possible to continuously inspect and adjust the image distortion without switching the inspection pattern or the anode current.

As a method of pre-storing the screen center position in the memory, the same shape as the picture tube to be inspected,
A jig in which a predetermined mark is formed at a position corresponding to the center position of the screen is set instead of the picture tube, and the center position of the screen can be determined from the image captured by the TV camera around the mark of the jig.

Further, the apparatus according to the present invention used in the display position adjusting method as described above, comprises a pattern generator for generating an inspection pattern having a luminance center of gravity at the center of the pattern, and adjusting the display position of the inspection pattern vertically and horizontally. A deflection power supply capable of performing the above operation, a pattern display position adjustment circuit for adjusting the pattern display position adjustment DC level given to the deflection power supply, and a TV for imaging the central portion of the inspection pattern projected on the picture tube.
A camera, a position detection circuit for obtaining the center position of the inspection pattern from the image captured by the TV camera, a memory for storing the center position of the screen of the picture tube in advance, and a shift between the center position of the inspection pattern and the center position of the screen. And a position control circuit for adjusting the pattern display position adjustment DC level based on the shift amount.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the image projected on the screen surface 2 of the inspected color picture tube 1 is
An image is taken by the TV camera 3 provided so as to face the screen surface 2, and the taken image information is input to the inspection mechanism 4. Although only one TV camera 3 is shown in the center in the figure, actually, a plurality of TV cameras are arranged in, for example, 5 columns and 5 rows, and the number of TV cameras is 25 in the image inspection after the display position adjustment.
An image of the point is taken.

The inspection mechanism 4 includes a position detection circuit 8 for detecting the position of the center of gravity of the luminance of the image captured by the TV camera 3, a position control circuit 9 for sending a correction signal corresponding to the amount of positional deviation to the deflection power source 5, and the detected data. For example, 512 columns horizontally, 47 columns vertically
The memory 10 stores position data on a matrix of 8 rows, and an image inspection circuit 11. Each circuit is collectively controlled by, for example, a microcomputer. The image inspection circuit 11 is, for example,
Inspecting misconvergence at 25 points on the screen surface, inspecting image distortion using 16 points on the outer periphery of the 25 points, using 2 points at both ends of the horizontal center row of the 25 points It is programmed to sequentially perform the yoke rotation inspection and the like to be performed.

The monitor 6 displays the image picked up by the TV camera 3, and further, when the mounting position of the TV camera 3 is displaced, the position stored in the memory 10 of the inspection mechanism 4 is adjusted so that the camera position can be adjusted. The data position and the image taken by the TV camera 3 can be displayed in an overlapping manner. That is, the mounting position can be calibrated by aligning the camera visual field center of the TV camera 3 with the camera defined position imaged by the TV camera 3, for example, the cross position on the white panel for indicating the measurement position standard. .

The position control circuit 9 of the inspection mechanism 4 monitors the display position of the inspection pattern displayed on the screen surface 2 of the picture tube 1 to be inspected automatically or by the inspection pattern taken in by the TV camera 3. It is connected to the deflection power source 5 via the pattern position adjustment circuit 12 so that the deflection power source can be supplied with a correction signal corresponding to the amount of positional deviation so that the adjustment can be performed manually while watching.

The pattern display position adjusting circuit 12 connected to the deflection power source 5 receives a correction signal corresponding to the amount of positional deviation from the outside, as in the case of MECC R-DEF, for example.
The deflection display power source 5 can be provided with a DC level for adjusting the pattern display position. Further, the pattern generator 7 that generates a predetermined inspection pattern, such as 1604A manufactured by LEADER, adjusts the misconvergence used in the image inspection circuit 11 and the multipoint dot signal for image distortion inspection, and the misconvergence visually. It is possible to generate a crosshatch signal for performing the above, and a raster signal for inspecting the image whiteness purity level. The deflection power source 5 is connected to the pattern generator 7 for synchronization.

Next, the image inspection method of the present invention using the inspection apparatus having the above-mentioned structure will be described. First, instead of the inspected color picture tube 1, as a jig for defining the center position of the screen surface, a cross mark is accurately drawn at a position corresponding to the center of the screen so that the mark can be picked up by a TV camera from the front side of the screen. A white panel of the same type as the color picture tube to be inspected having a structure in which a fluorescent lamp is mounted on the back side of the tube is set.

The position of the cross mark is stored in the memory 10 of the inspection mechanism 4 as the screen surface center position data by imaging the white panel with the TV camera 3 provided so as to face the screen surface 2. Further, a cross mark indicating the center position of the screen surface captured by the TV camera 3 is displayed on the monitor 6, and the mounting position of the TV camera 3 is adjusted so that the center of the field of view of the TV camera is aligned with the projected cross mark. In this way, the mounting position of the TV camera 3 with respect to the center position of the screen surface 2 is adjusted. T
By adjusting the mounting position of the V camera 3, it is possible to capture an image of the raster central portion in the vicinity of the center of the field of view of the camera, and as a result, the position adjustment range can be ensured vertically and horizontally.

Next, the center position data of the screen surface 2 stored in the memory 10 of the inspection mechanism 4 is retrieved and displayed on the monitor 6, and the position data is used as a reference to set the allowable range after adjusting the pattern display position. Is set and stored in the memory 10 of the inspection mechanism 4. This tolerance is
When the center position of the screen surface 2 is automatically adjusted, if the center position of the inspection pattern is controlled within the allowable range, the measurement error in the subsequent inspection is a control target range within a certain range. For example, in the case of a 36 cm (15 inch) high resolution color picture tube, a rectangular range of 0.5 mm vertically and horizontally from the center of the screen surface corresponds to this. The inspection pattern is 0.
When the image distortion inspection is performed in a state of being projected at a position separated by 5 mm or more, in addition to the image distortion of the color picture tube such as pincushion distortion, trapezoidal distortion due to the position shift of the inspection pattern is added. This makes it difficult to properly correct image distortion such as pincushion distortion.

Subsequently, the white panel as the jig for defining the center position of the screen surface is removed, the inspected color picture tube 1 (or an equivalent color picture tube) is set, and the pattern generator 7 is set.
The inspection pattern generated in step 1 is displayed on the screen surface 2 of the color picture tube. This inspection pattern is for inspecting misconvergence or image distortion, and is a multipoint dot pattern in which a plurality of luminance centroids at least the number of TV cameras (25) or more are arranged in a matrix including the pattern center. Is. Then, the dot located at the center of the inspection pattern is imaged by the TV camera 3 at the center.

Further, the position data of the center position of the screen surface 2 stored in the memory 10 and the center dot of the detected inspection pattern are superimposed and displayed on the monitor 6. The position control circuit 9 is manually adjusted while observing the center position data of the screen surface 2 and the image of the center dot displayed on the monitor 6 in order to determine the position where the inspection pattern is first displayed on the inspected color picture tube. Then, the center of the inspection pattern projected on the screen surface 2 and captured by the TV camera is made to coincide with the position data of the center position of the screen surface 2 displayed on the monitor 6, and the display position data of the inspection pattern is set. Is stored in the memory 10 of the inspection mechanism 4 as the initial display setting position. After that, when the inspection pattern is first displayed on another inspected color picture tube, it is displayed at the above-mentioned initial display setting position. This completes the condition setting.

Next, the color picture tube 1 to be inspected for actual image inspection is set, and the above-described multipoint dot inspection pattern generated by the pattern generator 7 is projected. The position at which the inspection pattern is displayed at this time is set to the initial display setting position stored previously. However, when the variation in the display position due to the variation in the assembly accuracy is relatively small, this step of adjusting the display position to the initial display setting position can be omitted.

Then, in order to perform automatic pattern position control, the central dot of the inspection pattern projected on the screen surface 2 is detected by the central TV camera 3 and sent to the position detection circuit 8, and the position detection circuit 8 inspects it. The luminance centroid position of the center dot of the pattern is calculated. Then, the position control circuit 9 calculates the amount of deviation between the calculated inspection pattern initial display position and the automatic adjustment target position stored in the memory 10,
A correction signal corresponding to the shift amount is given to the pattern display position adjusting circuit 12. The pattern display position adjusting circuit 12
A correction signal corresponding to the amount of deviation is converted into a DC level for adjusting the pattern display position and sent to the deflection power source 5. In this way, the inspection pattern display position is automatically adjusted. If the center of the inspection pattern is not within the allowable range from the center of the screen surface by one automatic adjustment, the amount of deviation from the center of the screen surface 2 is calculated again, and the above control is repeated. May be.

After the display position adjustment as described above is completed, the same inspection pattern can be used as it is to perform image distortion inspection such as trapezoidal distortion and pincushion distortion. In addition,
As the pattern position adjustment inspection pattern, for example, a pattern displaying one dot at the center of the pattern may be used instead of using the multi-point dot inspection pattern for measuring misconvergence or image distortion. In short, any inspection pattern may be used as long as the inspection pattern has a luminance centroid peak portion in the center of the image.

Further, the screen surface center position defining point formed on the white panel as the screen surface center position defining jig is not limited to the above-mentioned cross mark, but the center position can be recognized from the image taken by the TV camera. Any mark may be used. However, the cross mark is advantageous in that it can also be used for adjusting the rotation of the camera axis.

[0027]

As described above, according to the display position adjusting method and apparatus of the present invention, the efficiency of the adjusting work reduces the burden on the operator and the stable adjusting accuracy is maintained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a display position adjusting device for a picture tube according to an embodiment of the present invention.

[Explanation of symbols]

 1 Picture tube to be inspected 2 Screen surface of picture tube to be inspected 3 TV camera 4 Inspection mechanism 5 Deflection power supply 7 Pattern generator 8 Position detection circuit 9 Position control circuit 10 Memory

Claims (4)

[Claims] 1. A central portion of a screen of a picture tube on which an inspection pattern having a luminance center of gravity is projected at a pattern center is imaged by a TV camera, and a display position of the picture tube is adjusted based on the obtained image information. A method for adjusting the display position of a picture tube, comprising: taking a picture so that only one luminance centroid of the inspection pattern falls within the visual field of the TV camera, and centering the examination pattern on the basis of the luminance centroid of the obtained image. A picture tube characterized in that the difference between the obtained center position of the inspection pattern and the center position of the screen stored in advance in the memory is calculated, and the pattern display position adjustment DC level is adjusted based on this deviation amount. Display position adjustment method. 2. The inspection pattern has a plurality of brightness centroids arranged in a matrix including the pattern center, and is used for inspection and adjustment of image distortion after adjusting the display position of a picture tube. Item 1. A display position adjusting method for a picture tube according to item 1. 3. A picture tube having a jig having the same shape as a picture tube to be inspected and having a predetermined mark formed at a position corresponding to the picture center position in order to store the picture center position in the memory in advance. 2. The display position adjusting method of the picture tube according to claim 1, further comprising the step of setting the position of the jig and determining the center position of the screen from an image taken by a TV camera around the mark of the jig. 4. An apparatus used in the method according to claim 1, wherein a pattern generator for generating an inspection pattern having a luminance center of gravity at the center of the pattern, and a deflection device capable of adjusting the display position of the inspection pattern vertically and horizontally. Power source, pattern display position adjusting circuit for adjusting the pattern display position given to the deflection power source, a pattern display position adjusting circuit, a TV camera for capturing the central portion of the inspection pattern projected on the picture tube, and an image captured by the TV camera A position detection circuit for obtaining the center position of the inspection pattern from the memory, a memory for pre-storing the screen center position of the picture tube, a deviation between the center position of the inspection pattern and the screen center position is calculated, and based on the deviation amount, A display position adjusting device for a picture tube comprising a position control circuit for adjusting a pattern display position adjusting DC level.